Stretch-blow molding method for manufacturing balloons for medical devices

A process for fabricating medical device balloons, the process comprising:

• feeding an elongated tubularly shaped parison through a molding apparatus including a free-blow biaxial orientation chamber and a downstream blow molding chamber;
• longitudinally stretching to axially orient the parison within the free-blow chamber to provide an axially oriented parison length;
• biaxially orienting the axially oriented parison length by infusing pressurized fluid thereinto while same is within the free-blow chamber to provide a biaxially oriented parison length;
• axially stretching the biaxially oriented parison length;
• blow molding the biaxially oriented and axially stretched parison length, said blow molding step including raising the temperature of the biaxially oriented and axially stretched parison within the downstream blow molding chamber and infusing the pressurized fluid into a portion of the elongated parison that is upstream of the free-blow chamber whereby the pressurized fluid flows through the parison within the free-blow chamber and then into the biaxially oriented and axially stretched parison within the downstream blow molding chamber;
• closing off the parison between the free-blow chamber and blow molding chamber to prevent passage of pressurized fluid therebetween, and biaxially orienting the longitudinally oriented parison at an elevated temperature within the free-blow chamber to form another biaxially oriented parison length;
• and
• axially stretching said another biaxially oriented parison length, followed by blow molding same within the blow molding chamber at an elevated temperature to provide a molded parison useful as an angioplasty balloon.